1. Field of the Invention
The present invention relates to an organic light emitting device (OLED) in which a binaphthalene derivative is used as the emissive layer and/or one or more of the charge transport layers, or as a host or dopant material for one or more of such layers.
2. Description of the Related Art
Significant efforts have been expended in developing suitable materials for use in organic light emitting devices (OLEDs). Such devices are commercially attractive because they offer the promise of low-cost fabrication of high-density pixeled displays exhibiting bright electroluminescence with long life times and a wide range of colors.
A typical OLED is fabricated by sandwiching an emissive layer between an anode and a cathode. Improved performance can be obtained by the provision of additional layers around the emissive layers so as to provide charge transport capabilities, such as an electron transport layer or a hole transport layer. Some of these layers can be combined. For example, a double-layered structure is fabricated from a combined hole-injecting and transporting layer together with a combined electron-transporting and light-emitting layer. Likewise, a triple-layered structure is composed of a hole-injecting and transporting layer, a light-emitting layer, and an electron-injecting and transporting layer.
In addition, it is possible to form these layers from a host material doped with another material designed to achieve the desired effect of the layer (that is, to achieve a hole transport effect, an electron transport effect, or an emissive effect).
Because of consumer expectations of good efficiency, long life time and pure color, a need exists for development of suitable materials for the various layers.